Examples of information platforms supporting an IT system such as an Internet site are servers which are WEB servers, application servers, etc., storage devices for saving the data in database servers, and network switching devices for connecting servers and storage devices. Each year, the services provided by IT systems are becoming more diversified with more advanced features, an increasing number of information platforms and increasing system complexity. In order to cope with this state of affairs, in recent years, plural servers are now being mounted in one cabinet, and blade servers, which are space-saving and reduce the complexity of power supplies and network cabling, are coming into use. In a blade server, the server is high-density, since the parts of the server such as the CPU, memory and HDD are housed in a thin case known as a blade, plural blades being housed in a case called an enclosure. This type of blade server is disclosed in JP-A No. 32153/2002. On the other hand, in storage devices and network switching devices, the component elements of the device are modularized in order to ensure scalability of efficiency, and are connected with the enclosure only to the extent required to maintain performance. For example, in a storage device, a RAID controller and an HDD disk unit are modularized, and the RAID controller is duplicated to provide scalability of storage capacity. In a network switching device, an external I/F function part known as a line card is modularized to provide scalability of throughput capacity of the switch. Thus, in current information platforms, the component elements of the platform are modularized for each platform. A storage device of this type is disclosed in JP-A No. 50749/2003, and a network switching device of similar type is disclosed in JP-A No. 215116/2004.